长江口九段沙湿地大型底栖动物群落结构的季节变化规律

Seasonal fluctuation of macrobenthos community in Jiuduansha intertidal wetland of Yangtze River Estuary.

2004年11月至2005年10月,调查了长江口九段沙湿地大型底栖动物群落特征的季节变化及其土壤因子影响,共调查到大型底栖动物30种,主要由甲壳动物、环节动物、软体动物及昆虫幼体组成,光滑狭口螺(Stenothyraglabra)、堇拟沼螺(Assimineaviolacea)、焦河蓝蛤(Potamocorbulaustulata)、中国绿螂(Glau-comyachinensis)和谭氏泥蟹(Ilyrplaxdeschampsi)为优势种,且生物密度四季变化明显.春季大型底栖动物生物密度和生物量处于最高水平,多样性指数最高.夏季密度和生物量最低,物种多样性也较低,分布较不均匀.秋、冬季生物种类数与生物量差异不显著,生物密度冬季较秋季高.春、夏、秋季底栖动物种类数、密度和生物量均未与土壤因子达到显著相关水平.冬季土壤湿度与有机质含量与底栖动物密度显著相关.

From November 2004 to October 2005, an investigation was made on the seasonal fluctuation of macrobenthos community in the Jiuduansha intertidal wetland of Yangtze River Estuary, with the correlations between this fluctuation and sediment factors studied. 864 samples were collected seasonally from 216 sites in 7 sampling transects. A total of 30 species were identified, mainly belonging to Mollusca, Annelida, Crustacea and insect. The dominant species were Stenothyra glabra, Assiminea violaeea. Potamocorbula ustulata, Glaucomya chinensis, and llyrplax deschampsi. In spring, macrobenthos had the highest density and biomass and the richest diversity, but in summer, the density and biomass were the lowest, the diversity was on a lower level, and the distribution was uneven. There were no significant differences in the species number and biomass between autumn and winter, but the density was higher in winter than in autumn. In spring, summer and autumn, the species number, density, and binmass of macrobenthos had no significant correlations with sediment factors, but in winter, macrobenthos density had significant correlations with the humidity and organic matter content of sediment.